Reversing Systems

FAR 23.2420 Reversing Systems

FAR 23.2420 requires Part 23 airplane reversing systems to operate safely and allow continued safe flight and landing after any single failure or malfunction.

In Plain English

FAR 23.2420 is a Part 23 airworthiness design standard governing thrust or propeller reversing systems on small airplanes. It sets two basic safety requirements that manufacturers must meet during certification:

  • No unsafe condition during normal operation. When the reversing system is used as intended (for example, after touchdown), it must not create a hazard to the airplane or its occupants.
  • Continued safe flight and landing after failures. The airplane must remain controllable and able to land safely after any single failure, any likely combination of failures, or a malfunction of the reversing system.

Why it matters operationally: a reverser that deploys inadvertently in flight, fails to stow, or hangs up on landing can be catastrophic. This rule forces designers to build in fail-safes, redundancy, and proper warning so that a reverser malfunction never leaves the pilot without a path to a safe landing. As a pilot, knowing the certification basis helps you understand why your AFM has specific procedures for reverser malfunctions and inadvertent deployment.

Regulation Text
14 CFR § 23.2420
§ 23.2420 Reversing systems. Each reversing system must be designed so that— (a) No unsafe condition will result during normal operation of the system; and (b) The airplane is capable of continued safe flight and landing after any single failure, likely combination of failures, or malfunction of the reversing system.
Oral Exam Questions a DPE Might Ask
Q1What does FAR 23.2420 require of a reversing system on a Part 23 airplane?
Per FAR 23.2420, the reversing system must be designed so no unsafe condition results during normal operation, and the airplane must be capable of continued safe flight and landing after any single failure, likely combination of failures, or malfunction of the system.
Q2If a reverser malfunctions in flight, what level of safety must the design provide under FAR 23.2420?
FAR 23.2420(b) requires that the airplane remain capable of continued safe flight and landing after any single failure, likely combination of failures, or malfunction of the reversing system.
Q3Does FAR 23.2420 apply only to failures, or also to normal use of the reverser?
It applies to both. FAR 23.2420(a) requires no unsafe condition during normal operation, and 23.2420(b) addresses failures and malfunctions, ensuring continued safe flight and landing.
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FAR 23.2420 — Reversing Systems Safety Requirements